LTE, which stands for Long Term Evolution, is based on standards developed by the 3rd Generation Partnership Project (3GPP). LTE compliant systems allow peer to peer devices, e.g., LTE peer user equipment devices (UEs), to discover each other's application or service identifier announcements via listening to a common discovery channel. When the distance between the two UE's becomes larger than a certain range, or when the radio propagation between the UE that is announcing discovery information, sometimes referred to as the announcing UE, and the monitoring UE that is monitoring and seeks to detect the discovery information fades due to adverse channel conditions, the monitoring UE will loose track of the announcing UE.
Without the knowledge of the location of the announcing UE it is difficult to reach out to the infrastructure base station (eNodeB) serving the announcing UE. This is because in current LTE systems, infrastructure/system does not track the announcing UE's service/application identifiers. Thus, the monitoring UE, and its serving eNodeB are unable to determine the right route/path through eNodeBs to reach the announcing UE, although the announcing UE may be within the proximity of the monitoring UE.
UE's could be required to routinely provide, via WAN signaling, information to an infrastructure element about service/application identifiers the UE is advertising for peer to peer purposes so that the LTE infrastructure is aware of the location of the various UEs and the service/application identifiers they are advertising thereby making such information readily available to the infrastructure elements should a UE request such information from an infrastructure element. However, such an approach requires the UEs to frequently stay out of “idle” mode and frequently bring up an LTE WAN connection to update the information, which impacts the battery life of the UEs negatively. Accordingly, it should be appreciated that requiring UEs to register, via a WAN connection, information about the application and/or service identifiers they are advertising over a peer to peer, e.g., direct device to device, channel can be undesirable from a power consumption standpoint as well as from the standpoint of consuming WAN communications resources that might be used by other devices to communicate data over the WAN.
In view of the above discussion, it should be appreciated that there is a need for methods and apparatus which allow for an infrastructure element such as a base station to assist in peer discovery without requiring advertising peer to peer devices to register the identifiers to be advertised with an infrastructure element.